Drive for programmable sewing apparatus

ABSTRACT

An improved drive for programmable sewing apparatus for linearly moving a carriage of the sewing apparatus in increments along an axis under control of a programmer comprising a rotary power shaft, means for continuously driving the shaft, a driven member movable along the shaft, means interconnecting the driven member and the carriage, a plurality of rollers carried by the driven member, each roller having its axis of rotation disposed for rolling contact of the roller with the shaft, and means mounting the rollers for movement with the driven member and for pivotal movement of each of the rollers about an axis in a plane perpendicular to the axis of rotation of the roller. Each roller is pivotally movable about its pivotal axis from a neutral position in which its axis of rotation is parallel to the axis of the shaft for rotation of the roller by the shaft without traverse of the carriage along the shaft to an angled position in which its axis of rotation is skewed with respect to the axis of the shaft for linear movement of the carriage along the shaft. Means is also provided operable by the programmer for pivotally moving the rollers about their respective pivotal axes to effect movement of the carriage in one direction or the other along the shaft. This means is interconnected with the rollers to cause the rollers to return to their neutral position in response to movement of the carriage.

United States Patent 1 Conner, Jr.

[11] 3,842,766 Oct. 22, 1974 DRIVE FOR PROGRAMMABLE SEWING APPARATUS [75] Inventor: William R. Conner, Jr., Shelbyville,

Tenn.

[73] Assignee: Stahl-Urban Company, Brookhaven,

Miss.

[22] Filed: Nov. 1, 1973 [21] Appl. No.: 411,777

52 us. c1. 112/121.12, 7'4/25 [51] Int. Cl D05b 21/00, F16h 21/16 [58] Field of Search l12/121.12, 121.15, 102, 112/90, 86, 118; 74/22 R, 25

[56] References Cited UNITED STATES PATENTS 402,674 5/1889 Judson 74/25 579,614 3/1897 Steward et a1. 112/118" 2,578,026 12/1951 Taylor 7 4/25 X 2,940,322 6/1960 Uhing 74/25 X 3,072,081 l/l963 Milligan et al ll2/l2l.l2 3,329,109 7/1967 Portnoff et al....... ll2/l2l.l2 3,394,599 7/1968 Tuckerm. 74/25 3,473,393 l0/l969 Zaruba 74/25 Primary Examiner-James R. Boler [5 7 ABSTRACT An improved drive for programmable Sewing apparatus for linearly moving a carriage of the sewing apparatus in increments along an axis under control of a programmer comprising a rotary power shaft, means for continuously driving the shaft, a driven member movable along the shaft, means interconnecting the driven member and the carriage, a plurality of rollers carried by the driven member, each roller having its axis of rotation disposed for rolling contact of the roller with the shaft, and means mounting the rollers for movement with the driven member and for pivotal movement of each of the rollers about an axis in a plane perpendicular to the axis of rotation .of the roller. Each roller is pivotally movable about its pivotal axis from a neutral position in which its axis of rotation is parallel to the axis of the shaft for rotation of the roller by the shaft without traverse of the carriage along the shaft to an angled position in which its axis of rotation is skewed with respect to the axis of the shaft for linear movement of the carriage along the shaft. Means is also provided operable by the programmer for pivotally moving the rollers about their respective pivotal axes to effect movement of the carriage in one direction or the other along the shaft. This means is interconnected with the rollers to cause the rollers to return to their neutral position in re-- sponse to movement of the carriage.

30 Claims, 7 Drawing Figures DRIVE FOR PROGRAMMABLE SEWING APPARATUS BACKGROUND OF THE INVENTION This invention relates to an improved drive for moving a carriage in increments along an axis under the control of a programmer and more particularly to a drive for moving the cloth holding carriage of programmable sewing apparatus along a predetermined path at high speed without guidance from an operator.

This invention represents an improvement over such programmable sewing apparatus as heretofore known, such as exemplified by the punch-tape-controlled sewing apparatus disclosed in my copending U.S. Pat. application Ser. No. 235,253, filed Mar. 16, 1972, issued as U.S. Pat. No. 3,771,477, Nov. 13, 1973. Heretofore, the carriage holding the cloth pieces to be sewn was incrementally moved in steps along X and Y axes in a specified manner by stepping motors energized in response to a punch-tape controller. These stepping motors were connected directly to the carriage and provided the force for moving the carriage in the programmed manner. However, the stepping motors, especially when sewing at high speeds and around sharp corners, tended to move the cloth unevenly past the sewing machine needle, thus resulting in uneven stitching. This uneven stitching was due primarily to high accelerations and decelerations imparted to the carriage by the stepping motors and the inertia of the carriage. These inertial forces may become quite large, especially if the programmer causes the stepping motors to step at a rate corresponding to the natural frequency of the carriage. This has caused the carriage of prior art sewing apparatus to miss steps and to result in uneven stitching. Linear drives broadly similar to the improved drive of this invention are generally shown in such U.S. Pat. Nos. as 402,674, 2,578,026, 2,940,322 and 3,473,393.

SUMMARY or THE'INVENTION Among the several objects of this invention may be noted the provision of an improved drive for moving the carriage of programmable sewing apparatus in such manner as to accelerate and decelerate the carriage in a relatively smooth manner, thus preventing uneven stitching by the sewing apparatus; the provision of such a drive which may be readily controlled by a programmer to move the carriage along any predetermined path; the provision of such a drive in which the power for moving the carriage is supplied by a continuously driven power shaft and by a discrete actuator, such as a stepping motor; the provision of such a drive which moves the carriage at high speed; the provision of programmable sewing apparatus including such an improved drive of this invention which is safe to operate; the provision of such apparatus which does not require a skilled operator; the provision of such apparatus which quickly and accurately stitches work thus resulting in greater production and in saving of material because of fewer rejected pieces; and the provision of such apparatus which is reliable in operation, economical to maintain, and which significantly increases the output and quality of the pieces sewn thereby. Other objects and features will be in part apparent and in part pointed out hereinafter.

Briefly, animproved drive of this invention for linearly moving a driven member in increments along an axis under control of a programmer comprises a rotary power shaft, means for continuously driving the shaft, a plurality of rollers carried by the driven member, each roller having its axis of rotation disposed for rolling contact of the roller with the shaft, and means mounting each roller for movement with the driven member and for pivotal movement about an axis in a plane perpendicular to the axis of the roller. Each roller is pivotally movable about its pivotal axis from a neutral position in which its axis of rotation is parallel to the axis of the shaft for rotation of the roller by the shaft without traverse of the driven member along the shaft to an angled position in which its axis of rotation is-skewed with respect to the axis of the shaft for linear movement of the driven member along the shaft. Also provided are means operable by the programmer for pivotally moving the rollers about their respective pivotal axes to effect movement of the driven member in one direction or the other along the shaft, these means being interconnected with the rollers to cause the rollers to return to their neutral position in response to movement of the driven member. I

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of programmable sewing apparatus utilizing the improved drive of this invention;,

FIG. 2 is a front elevational view of the apparatus shown in FIG. 1;

FIG. 3 is a right end elevational view of FIG. 1; FIG. 4 is an enlarged vertical section on line 44 of FIG. 1 illustrating details of the improved drive of this invention including a driven member, a rotary power shaft and a plurality of rollers in rolling contact with the shaft;

ther illustrating details of the improved drive and showing the rollers in their neutral positions relative to the power shaft in which the drive means remains stationary with respect to the shaft;

FIG. 6 is a view similar toFIG. 5, but with the rollers in an angled position in which the rollers and the driven member move linearly along the shaft; and

FIG. 7 is an enlarged portion of FIG. 3 illustrating further details of the drive of this invention.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, programmable sewing apparatus of the present invention is designated generally by the reference numeral 11 and is adapted for automatic high-speed sewing under the control of a punch-tape controller or programmer 12. The apparatus includes a sewing machine 13 (shown in phantom in FIG. 1 for clarity) of a conventional electrically driven industrial type. Sewing machine 13 is suitably mounted on and supported by a frame 15. As illustrated, the apparatus is especially configured for automatically sewing a shirt collar profile, i.e., along the margins of shirt collar material. Of course, it will be understood that a variety of different patterns can be sewn by the apparatus on fabric or other materials.

FIG. 5 is a vertical section on line 55 of FIG. 4 fur- The apparatus comprises a positioning means, as indicated generally at 16, including a carriage l7 and a clamp 18 carried by the carriage for clamping and effecting relative movement of material to be sewn (e.g.,

layers of shirt collar fabric which may be referred to as a workpiece) with respect to the needle 19 (also referred to as a work point) of sewing machine 13 along a desired sewing path on at least two possible axes of movement. Movement of the carriage and the clamp for this positioning purpose according to a predetermined pattern is determined by a punch tape. The carriage 17 comprises a table 21 for supporting layers of fabric to be sewn and several clamp elements or fingers 23. Fingers 23 are hinged in sets and are adapted to be raised for placing fabric on table 21 or to be lowered for clamping fabric against the table by a pair of small air cylinders 24a,24b. The table 21 and fingers 23 are movable as a unit either longitudinally along an X axis or laterally along a Y axis with respect to frame and sewing machine 13; these axes being so designated in F IG. 1. It will be understood that clamp 18 and table 21 constitute a work holder for the cloth to be'sewn.

Linear movement of carriage 17 along the X and Y axes is effected by operation of an improved drive of this invention, as indicated generally at 25. More particularly, drive 25 comprises an X axis drive 27 and a Y axis drive 29, each being operable for moving the carriage in increments along a respective X or Y axis under control of programmer 12. X drive 27 comprises a discrete stepping motor 31 (see FIG. 2) secured to frame 15 and a linearactuator 33 actuable in response to stepping of stepping motor 31 to move the carriage stepwise along the X axis. Y drive 27 comprises a discrete stepping motor 35 and a linear actuator 37 actuable in response to stepping of stepping motor 35 to move the carriage stepwise along the Y axis. Linear actuators 33 and 37 will be described in detail hereinafter. It will be understood that discrete stepping meters 31 and 35 provide incremental or stepwise rotation of their output shafts in response we pulsed input to the motor windings from programmer 12. The step size and stepping rate of these motors may vary, but preferably the step size is selected to effect movement of carriage 17 in 0.020 inch increments and at a rate commensurate with the maximum sewing speed of sewing machine 13.

Carriage 17 is supported on frame 15 for biaxial movement along the X and'Y axes by so-called ball bushings or slider bearing assemblies 39a,39b adapted to slide freely and linearly along a respective rod 41a,41b of circular cross section (each such rod constituting a linear bearing surface). Each of rods 41a,41b is secured at opposite ends to frame 15 by brackets 43 for linear movement of bushings 39a,39b along the X axis. Bushings 39a and 39b carry transversely oriented rods 45a and 45b by means'of bracket structure 46 (FIG. 3). Ball bushings 47a and 47b, similar to bushings 39a and 39b, constitute sliders adapted to slidelinearly back and forth along rods 45a and 45b, respectively (these rods constituting linear bearing surfaces), and

thus along the Y axis. A bar 49 extends between bushings 4711,4712, each end of the bar being secured by a respective arm 51a,5lb to bushings 47a and 47b, respectively. Bar 49 carries clamp 18 and is adapted to be moved back and forth along the Y axis parallel to the X axis through operation of stepping motor 35. Bar 49, clamp 18 and its associated assemblies and'bushings together may be regarded as carriage 17, the entire carriage being incrementally movable along either the X or Y axis.

For the purpose of moving carriage 17 along the Y axis, Y drive 29 includes a shaft 53 at the rear of frame 15 extending longitudinally along the length of the.

frame and journalled at its ends to the frame. A sprocket 55 on shaft 53 and sprockets 57 are driven via a chain belt 59. by stepping motor 35 via linear actuator 37. Shaft 53 carries three sprockets 61a,61b and 63 in addition to sprocket 55 around which pass respective chain belts 65a,65b.and 67. These chain belts are tensioned by respective idlers 69a,69b and 71. Rods 73a and 731) are carried between pairs of these chain belts, i.e., the ends of rods 73a are connected to belts 65a and 67a and the ends of rods 73b are connected to belt 65b and 59. Thus, rods 73a and 7312 are together shifted along the Y axis by operation of stepping motor 35 and linear actuator 37. Each of rods 73a,73b has on it a respective ball joint rod end bearing 750,75!) adapted to slide freely along the respective rod. Respective links 77a,77b interconnect the bearings a,75b with arms 51a,'51b.

Accordingly, when shifted along the X axis, carriage 17 is maintained in parallel relationship with the X axis since slide bearings 75a,75b slide freely along their respective rods 7311,7317. However, upon stepwise rotation of the output shaft of stepping motor35 of Y drive 29, chains 65a,65b and 67,59 shift rods 73a,73b toward and away from the X-axis. Thus, carriage 17 is shifted along the Y axis through operation of stepping motor 35.

More particularly, linear actuators 33and 37 of X drive 27 and Y drive 29, respectively, are similar, and thus only linear actuator 33 for X drive 27 need be described in detail, with pertinent differences between the linear actuators particularly pointed out. Linear actuator 33 comprises a rotary power shaft 79 continuously driven by a belt 80 from a motor 81. Shaft 79 is a smooth cylindric shaft extending parallel to the X axis (or in the case of linear actuator 37, parallel to the Y axis). Shaft 79 is journalled in bearings 83.

Linear actuators 33 and 37 each comprise a plate or driven member joined to a portion of the carriage and movable with the carriage. Driven member 85 carries a plurality of rollers 87 each having its rotary axis disposed for rolling contact of the roller with shaft 79. Driven member 85 of linear actuator 33 is secured directly to carriage 17, and driven member 85 of Y drive 29 is joined to the carriage by means of chain belts 59, 67 and 650,651) as described above. In both X drive 27 and Y drive 29, driven members 85 are movable with the carriage. As shown in FIGS. 3" and 7, driven member 85 of linear actuator 37 is secured to a slider bearing 88 slidable along a rod 89 generally parallel to the Y axis, this rod being secured to frame 15. Chain belt 59 is secured to driven member or plate 85, as indicated at 90, so that upon movement of the driven member, chain belt 59 is caused to move around its respective sprockets and to thus effect movement of the carriage along the Y axis as described above.

As shown in FlGS. 4-6, driven member or plate 85 surrounds shaft 79 and carries a plurality of bearing blocks 91, one for each roller 87, mounting the rollers for pivotal movement about an axis in a plane perpendicular to the axis of rotation of the rollers. More specifically, each roller 87 is joumalled on an axle bolt 92,

the axial center line of this axle bolt constituting the axis of rotation of the roller. Each axle bolt 92 is supported by a clevis 93 and a shaft 95 is secured to each clevis in such manner that bolt 92 is offset from the axial center line of the shaft. Each shaft is journalled in a respective bearing block 91 and is pivotally rotatable about its longitudinal axis in the above-mentioned plane perpendicular to the axis of rotation of the rollers for movement between a neutral position (see FIG. 5) in which the axis of rotation of the roller (i.e., the longi-, tudinal axis of axle bolt 92) is parallel to the longitudinal axis of shaft 79 for rotation of the roller by the shaft without traverse of driven member 85 or carriage 17 along the shaft to an angled position (see FIG. 6) in which the axis of rotation of the roller is skewed with respect to the axis of shaft 79 for effecting linear movement of driven member 85 and carriage 17 along the shaft. With the roller in its angled position (as is shown in FIG. 6), the angle formed between the axis of rotation of the roller and the longitudinal axis of shaft 79 is referred to as a pitch angle because it corresponds generally to the pitch angle of a threaded power screw. It will be noted that shaft 79 has a smooth outer surface and thus rollers 87 are caused to roll on the outer surface of the shaft and to trace a helical path thereon to advance the driven member along the shaft. Because the shaft is smooth, the distance the rollers or the driven member will traverse along a shaft for each revolution of the shaft (i.e., the pitch) is infinitely variable, depending on the pitch angle of the rollers. An O-ring 96 of resilient material, such as rubber, is interposed between a bearing block 91 of one of the rollers 87 and the adjacent clevis 93, so that with the rollers in rolling contact with shaft 79 (as shown in FIG. 4) the O-ring is compressed and thus constitutes means for resiliently biasing the rollers into rolling contact with the shaft.

It will be understood that stepping motors 31 and 35 and respective chain belts 97 and 99 constitute means, as indicated generally at 101, interconnected with the rollers of their respective linear actuators 33 and 37 to cause the rollers to move from their respective neutral positions to their angled positions in response to a signal generated by programmer 12 and to cause the rollers to return to their neutral positions in response to movement of the carriage or plate 85 along shaft 79.

Means 101 further includes a crank 103 secured to the outer end of shaft 95 of one of the rollers 87, constituting a master roller as specifically indicated at 87a (see FIG. 4) to distinguish it from the other rollers 87, so that upon rotation of the crank, shaft 95 is rotated relative to its respective bearing block 91 so as to effect pivotal movement of the master roller carried thereby between its neutral and angled positions. As best shown in FIGS. 5 and 6, crank 103 is interconnected to one reach of its respective chain belt 97 or 99 (depending on whether it forms a part of linear actuator 33 or 37). Chain belt 97 of linear actuator 33 is trained around a sprocket 105 fixed on the output shaft of stepping motor 31 and around sprockets 107a,107b and 107c (see FIG. 2). The upper reach of the chain belt passes through an opening 109 in plate 85 of linear actuator 33 and is interconnected to crank 103 by a pivot link 110. Thus, upon stepping of stepping motor 31, the upper reach of the chain is moved in one direction or the other depending on the direction of rotation of the stepping motor. This stepping of the stepping motor and consequent movement of chain 97 causes the crank to rotate and to effect movement of the rollers to their angled positions. Similarly, chain belt 99 of linear actuator 29 is trained around a sprocket 111 of stepping motor 35 and a sprocket 113 forming an upper reach and a lower reach. Like chain belt 97, the upper reach of chain belt 99 of linear actuator 37 passes through an opening 109 in plate and is fastened to crank 103 by means of a pivot link 110. It will be understood that upon reverse rotation of the output shaft of either of the stepping motors 31 or 35, reverse movement-of the carriage along the respective shafts 79 will be effected.

Means 101 also includes a linkage generally indicated at 115 (see FIG. 4) interconnecting the rollers 87 of each linear actuator 33 or 37 for maintaining the rollers at the same pitch angle. Linkage 115 comprises a movable or rotary ring 117 surrounding shaft 79 and rotatably carried by plate 85. As best shown in FIGS. 5 and 6, ring 117 is held captive on one face of plate 85 by means of a collar 119 surrounding an opening 121 for shaft 79 in plate 85, this collar being secured to the plate 85. A flange 123 is secured to collar 119 and extends outwardly beyond the collar. Ring 117 is somewhat thinner than collar 119 and has an inner opening of somewhat larger cross section than the outer diameter of the collar so as to permit the ring freely to rotate on plate 85 and on collar 119 about the longitudinal axis of shaft 79. A rod end 124 constituting first spherical bearing means is connected, as by bolt 125, to clevis 93 of master roller 87a to which crank 103is connected. The threaded end 126 of rod end 124 is received in the bore of a spherical bearingat one end of a second rod end 127 having its other end secured to movable ring 117. It willbe understood that upon rotation of crank 103 with consequent pivotal movement of master roller 87a between its neutral and angled positions, rod end 124 is caused to rotate with the master roller about the pivotal axis of the roller (i.e., about the center line axis of its shaft This movement of the rod end includes a component of force into the plane of ring 117 and a component parallel to the plane of the ring. The spherical bearings of rod ends 124 and 127 accommodate limited rotational movement about any axis toward and away from the ring and the movement of the rod end 124 in the plane of the ring causes the rod end fitting 127'to'rotate the ring relative to plate 85. Each of the other rollers 87 is interconnected to the ring by a similar arrangement of rod ends. Upon movement of the ring, the rod end fittings 127 of the other rollers transfer the rotary movement of the ring to their clevises 93 thus effecting pivotal movement of the rollers to assume the same pitch angle as roller 87a. Thus, linkage 117 slaves the other rollers 87 to master roller 87a interconnected to crank 103. It will be understood that other linkage arrangements 'may be used so long as changes in pitch angle are possible.

In operation, carriage 17 is moved in a predetermined pattern in accordance with a punch tape (not shown) fed through punch-tape controller 12. The controller generates signals in response to codes carried by the punch tape. These signals initiate discrete stepping of stepping motors 31 and 35 in a predetermined manner so as to effect movement of the work held by table 21 and clamp 23 of carriage 17 past the work point or needle 19 of sewing machine 13 along a predetermined path for stitching of the work. Upon energization of either of the stepping motors 31 or 35, a respective chain respective linear actuator 33,37 is rotated. Upon rotation of crank 103, master roller 87a is moved from its neutral to its angled position and concurrently via link age 115 the other rollers 87 are rotated from their neutral positions to angled positions corresponding to'the position of roller 87a. Immediately upon moving from their neutral positions, rollers 87 begin to traverse along shaft 79 and thus to effect linear movement of plate 85 and carriage 17 interconnectedthereto along a respective X or Y axis. With stepping motors 31, 37 stopped, movement of plate 85 along its shaft 79 (as may be caused by the rollers in their angled positions) effects relative movement between the plate and its respective chain 97 or 99. This relative movement causes crank 103 to rotate in a reverse direction and to restore the rollers to their neutral positions and to thus halt movement of plate and carriage along shaft 79. If programmer 12 generates signals for effecting a series of steps of a stepping motor 31,35 in rapid succession, rollers 87 may remain in their angled positions without returning to their neutral positions. Thus, carriage 17 will be continuously moved along a respective axis at a I the carriage supplied by the stepping motors (eg, onethird or one-fourth of the total motive force) depends on the geometry of lirikagellS and the degree of offset of clevis 93 and crank 103 from the center line of shaft 95 (Le, the smaller the degree of offset, the smaller the force supplied by the stepping motor). With the rollers and linkage 115 as shown in FIG. 4, the majority of the motive force is supplied by the power shaft 79 acting through rollers 87 rolling thereon when the rollers are in their angled positions. Thus, linear actuators 33,37 may be referred to as a booster drive for stepping motors 31,35.- With rollers 87 offset from their respective pivot shafts 92 (as shown in FIG. 4) stepping motors 31 and 35 cause the rollers to pivot about their respective pivot axes and to move the rollers toward and away from driven member 85. With the rollers inengagement with shafts 79, this movement of the rollers toward and away from the driven member exerts a force on the driven member and on carriage 17 thus to effect movement of the carriage along the X or Y axis.

The improved drive of this invention enables the carriage of the sewing apparatus to be moved in steps having a step size generally the same as the step size os my previous programmable sewing apparatus as described in my above-mentioned copending patent application Ser. No. 235,253 (e.g.,. in discrete steps of approximately 0.020 inch) and at the same stepping rate. However, the primary advantages of the improved drive of this invention are smoother acceleration and deceleration of the carriage, thus resulting in more even stitching by the sewing apparatus, especially when sewing around sharp corners and other discontinuities, and the power being primarily supplied to the carriage by a continuously rotating shaft 79 rather than by intermittently operable stepping motors, with the balance of the power supplied to the carriage by the linear actuator (i.e., stepping motors 31,35). This last-mentioned advantage permits the use of smaller stepping motors. It will be understoodthat the offset of rollers 87 with respect to their respective pivot axes (i.e., the axis of shaft 95) may be varied or eliminated as desired and that a force will only be supplied to the driven member 85 and to carrier 17 from thestepping motors when the rollers 87 are offset.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A drive for linearly moving a driven member in increments along an axis under control of a programmer comprising a rotarypower shaft, means for continuously driving said shaft, a plurality of rollers carried by the driven member, each roller having its axis of rotation disposed for rolling contact of the roller with said shaft, means mounting each roller on the driven memher for pivotal movement about an axis in a plane perpendicular to the axis of rotation of the roller, each roller being pivotally movable about its pivotal axis from a neutral position in which its axis of rotation is parallel to the axis of the shaft for rotation of the roller by the shaft without traverse of the driven member along the shaft to an angled position in which its axis of rotation is skewed with respect to the axis of the shaft for linear movement of the driven member along the shaft, and means operable by said'prog rammer for pivotally moving said rollersabout their respective pivotal axes to ef-v fect movement of the driven member in one direction or the other along said shaft, said means being interconnected with said rollers to cause the rollers to return to their neutral position in response to movement of the driven member. 7 v

2. A drive as set forth in claim '1 wherein said pivotal axis of each roller is offset from its axis of rotation.

3. A drive as set forth in claim 1 wherein the angle of the axis of rotation of said rollers relative to the axis of said shaft when said rollers are in their said angled position constitutes a pitch angle and wherein said means for moving said rollers comprises linkage means interconnecting said rollers for maintaining the rollers at the same pitch angle.

4. A drive as set forth in claim 3 wherein said'means for pivotally moving said rollers comprises a discrete actuator and means interconnecting at least one of said rollers tosaid discrete actuator, the latter being operable in response to said programmer to effect movement of the rollers from their neutral positions to their angled positions so as to effect movement of the driven member along said shaft and upon movement of the driven member to return said rollers to their neutral positions thereby to halt movement of the driven member along the shaft; i

5. A drive as set forth in claim 4 wherein said discrete actuator is astepping motor rotary stepwise under the control of said programmer for incrementally moving said carriage along the shaft.

6. A drive as set forth in claim wherein said means interconnecting said rollers to said discrete actuator means comprises a crank connected to one of said rollers and chain means interconnected between said crank and the output shaft of said stepping motor whereby upon stepping of the stepping motor said crank is rotated to move said one roller and the others of said rollers via said linkage means from their respective neutral positions to their respective angled positions thereby to effect movement of the driven member along said shaft.

7. A drive as set forth in claim 6 wherein said chain drive means includes a plurality of sprockets around which a chain is trained with one reach of the chain extending generally parallel to the shaft, said one reach being connected to said crank and supplying a portion of the force applied to said driven member for moving the driven member along said shaft in relatively smooth steps thereby to insure even movement of the driven member.

8. A drive as set forth in claim 7 wherein a portion of said driven member at least partially surrounds said shaft and carries a plurality of bearing means, one for each roller, each bearing means supporting a respective roller for pivotal movement between its neutral and angled positions.

9. A drive as set forth in claim 8 wherein said linkage means comprises a rotary member carried by said driven member and at least partially surrounding said shaft, said rotary member being rotary about the axis of said shaft, first spherical bearing means connected to each of said rollers and second spherical bearing means, one for each roller carried by said rotary member and interconnected to a respective first spherical bearing means so that upon actuation of said stepping motor said one roller interconnected to said stepping motor effects rotation of the rotary member relative to the driven member via said first and second spherical bearing means connected thereto, the rotary movement of said rotary member effecting pivoting of the others of said rollers via their respective first and second spherical bearing means to assume an angled position corresponding to the angled position of said one roller.

10. A drive as set forth in claim 9 further comprising means for resiliently biasing said rollers into rolling contact with said shaft.

11. A drive as set forth in claim 10 wherein said resilient biasing means comprises spring means interposed between at least one of said bearing means and a respective roller for forcing said respective roller into engagement with said shaft and for drawing the others of said rollers into engagement with the shaft so that all of said rollers are driven by the shaft.

12. A drive as set forth in claim 1 having three of said rollers in rolling contact with said shaft.

13. Apparatus for moving a workpiece to a work point comprising:

positioning means including a carriage for holding the workpiece, said positioning means effecting relative movement of the workpiece held by the carriage with respect to said work point along at least two possible axes of movement for doing work on said workpiece along a predetermined path, one of said axes constituting an X axis and the other of said axes constituting a Y axis;

a drive for said carriage including an X axis drive for moving the carriage in increments along said X axis and a Y axis drive for moving the carriage in increments along said Y axis;

programmable control means for effecting actuation of said X and Y drives to move the carriage in increments along said X and Y axes in said predetermined path; and

each X and Y axis drive comprising a rotary power shaft, means for continuously driving said shaft, a driven member movable along the shaft, means interconnecting said driven member and said carriage, a plurality of rollers carried by the driven member, each roller having its axis of rotation disposed for rolling contact of the roller with said shaft, means mounting each roller on the driven member for pivotal movement about an axis in a plane perpendicular to the axis of rotation of the roller, each roller being pivotally mounted for rotation about its pivotal axis from a neutral position in which its axis of rotation is parallel to the axis of the shaft for rotation of the roller by the shaft without traverse of the driven member and the carriage along the shaft to an angled position in which its axis of rotation is skewed with respect to the axis of the shaft for linear movement of the driven member and the carriage along the shaft, and means operable by said programmer for pivotally moving said rollers about their respective pivotal axes to effectmovement of the driven member and the carriage in one direction or the other along said shaft, said means being interconnected with said rollers to cause the rollers to return to their neutral positions in response to movement of the carriage.

14. Apparatus as set forth in claim 13 wherein said pivotal axis of each roller is offset from its axis of rotation.

15. Apparatus as set forth in claim 13 wherein the angle of the axis of rotation of said rollers relative to the axis of said shaft when said rollers are in their angled positions constitutes 'a pitch angle and wherein said means for moving said rollers comprises linkage means interconnecting said rollers for maintaining the rollers at the same pitch angle.

l6. Apparatus'a's set forth in claim 15 wherein said means for pivotally moving said roll'e'rs comprises a descrete actuator and means interconnecting at least one of said rollers to saiddiscrete actuator, the latter being operable in response to said programmer to effect movement of the rollers from their neutral positions to their angled positions so as to effect movement of the carriage along said shaft and upon movement of the carriage to return saidrollers to their neutral positions thereby to halt movement of the carriage along the shaft.

17. Apparatus as set forth in claim 16 wherein said discrete actuator is a stepping motor rotary stepwise under the control of said programmer for incrementally moving said carriage along the shaft.

18. Apparatus as set forth in claim 17 wherein said means interconnecting said rollers to said discrete actuator means comprises a crank connected to one of said rollers and chain means interconnected between said crank and the output shaft of said stepping motor whereby upon stepping of the stepping motor said crank is rotated to move said one roller and the others of said rollers via said linkage means from their respective neutral positions to their respective angled positions thereby to effect movement of the carriage along said shaft.

19. Apparatus as set forth in claim 18 wherein said chain drive means includes a plurality of sprockets around which a chain is trained with one reach of the chain extending generally parallel to the shaft, said one reach being connected to said crank and supplying a portion of the force applied to said driven member for moving the carriage along said shaft in relatively smooth steps thereby to insure even movement of the carriage. E

20. Apparatus as set forth in claim 19 wherein a portion of said driven member at least partially surrounds said shaft and carries a plurality of bearing means, one for each roller, each bearing means supporting a respective roller for pivotal movement between its neutral and angled positions.

21. Apparatus as set forth in claim 20 wherein said linkage means comprises a rotary member carried by said driven member and at least partially surrounding said shaft, said rotary member being rotary about the axis of said shaft relative to said driven member, first spherical bearing means connected to each of said rollers and second spherical bearings means, one for each roller, carried by said rotary member and interconnected to a respective first spherical bearing means so that upon actuation of said stepping motor said one roller interconnected to said stepping motor effects rotation of the rotary member relative to the driven member via said f rst and second spherical bearing means connected thereto, the rotary movement of said rotary member effecting pivoting of the others of said rollers via their respective first and second spherical bearing means to'assume an angled position corresponding to the angled position of said one roller.

22. Programmable sewing apparatus comprising a sewing machine, a carriage for holding work to be sewn by the sewing machine, means for driving said carriage so as to effect movement of the work held by the carriage along a predetermined path relative to the sewing machine along at least two possible axes of movement, one of said axes constituting an X axis and the other of said axes constituting a Y axis, and programmable control means for effecting actuation of said drive means to move the carriage in increments along said X and Y axes on said predetermined path, said drive meanshaving an X drive and a Y drive each comprising a rotary power shaft, means for continuously driving said shaft, each roller having its axis of rotation disposed for rolling contact of the roller with said shaft, a driven member movable linearly along said shaft, means interconnecting said driven member to said carriage for move- "ment of the carriage along the shaft, a plurality of rollers movable with the driven member, means mounting "each roller on the driven member for pivotal movement about an axis'in a plane perpendicular to the axis of rotation of the roller, each roller being pivotally movable about its pivotal axis from a neutral position in which its axis of rotation is parallel to the axis of the shaft for rotation of the roller by the shaft without traverse of the carriage along the shaft to an angled position in which its axis of rotation is skewed with respect to the axis of the shaft for linear movement of the carriage along the shaft and means operable by said programmer for pivotally moving said rollers about their respec- 12 I I tive pivotal axes to effect movement of the carriage in one direction or the other along the shaft, said means being interconnected with said rollers to cause the rollers to return to their neutral positions in response to movement of the carriage.

23. Programmable sewing apparatus as set forth in claim 22 wherein said pivotal axis of each roller is offset from its axis of rotation.

24. Programmable sewing apparatus as set forth in claim 22 wherein the angle of the axis of rotation of said rollers relative to the axis of said shaft when said rollers are in their said angled position constitutes a pitch angle and wherein said means for moving said rollers comprises linkage means interconnecting said rollers for maintaining the rollers at the same pitch angle.

25. Programmable sewing apparatus as set forth in claim 24 wherein said means for pivotally moving said rollers comprises a descrete actuator and means interconnecting at least one of said rollers to said discrete actuator, the latter being operable in response to said programmer to effect movement of the rollers from their neutral positions to their angled positions so as to effect movement of the driven member and the car-V the shaft.

27. Programmable sewing apparatus as set forth in claim 26 wherein said means interconnecting said rollers to said discreteactuator means comprises a crank connected to one of said'rollers and chain means interconnected between said crank and the output shaft of said stepping motor whereby upon stepping of the stepping motor said crank is rotated to move said one roller and the others of said rollers via said linkageimeans from their respective neutral positions to their respective angled positions thereby to effect movement of the carriage along said shaft. 7

28. Programmable sewing apparatus as set forth in claim 27 wherein said chain drive means includes a plurality of sprockets around which a chain is trained with one reach extending generally parallel to the shaft, said one reach of the'chain being connected to said crank and supplying a portion of the force applied to said carriage for moving the carriage along said shaft in relatively smooth steps thereby to insure even movement of the carriage.

29. Programmable sewing apparatus as set forth in claim 27 wherein a portion of said driven member at least partially surrounds said shaft and carries a plurality of bearing means, one for each roller, each bearing means supporting a respective roller for pivotal movement between its neutral and angled positions.

30. Programmable sewing apparatus as set forth in claim 29 wherein said linkage means comprises a rotary member carried by said .driven, member and at least partially surrounding said shaft, said rotary member being rotary about theaxis of said shaft relative to said driven member, first spherical bearing means connected to each of said rollers and second spherical bearing means, one for each roller, carried by said romovement of said rotary member effecting pivotingof the others of said rollers via their respective first and second spherical bearing means to assume an angled position corresponding to the angled position of said one roller. 

1. A drive for linearly moving a driven member in iNcrements along an axis under control of a programmer comprising a rotary power shaft, means for continuously driving said shaft, a plurality of rollers carried by the driven member, each roller having its axis of rotation disposed for rolling contact of the roller with said shaft, means mounting each roller on the driven member for pivotal movement about an axis in a plane perpendicular to the axis of rotation of the roller, each roller being pivotally movable about its pivotal axis from a neutral position in which its axis of rotation is parallel to the axis of the shaft for rotation of the roller by the shaft without traverse of the driven member along the shaft to an angled position in which its axis of rotation is skewed with respect to the axis of the shaft for linear movement of the driven member along the shaft, and means operable by said programmer for pivotally moving said rollers about their respective pivotal axes to effect movement of the driven member in one direction or the other along said shaft, said means being interconnected with said rollers to cause the rollers to return to their neutral position in response to movement of the driven member.
 2. A drive as set forth in claim 1 wherein said pivotal axis of each roller is offset from its axis of rotation.
 3. A drive as set forth in claim 1 wherein the angle of the axis of rotation of said rollers relative to the axis of said shaft when said rollers are in their said angled position constitutes a pitch angle and wherein said means for moving said rollers comprises linkage means interconnecting said rollers for maintaining the rollers at the same pitch angle.
 4. A drive as set forth in claim 3 wherein said means for pivotally moving said rollers comprises a discrete actuator and means interconnecting at least one of said rollers to said discrete actuator, the latter being operable in response to said programmer to effect movement of the rollers from their neutral positions to their angled positions so as to effect movement of the driven member along said shaft and upon movement of the driven member to return said rollers to their neutral positions thereby to halt movement of the driven member along the shaft.
 5. A drive as set forth in claim 4 wherein said discrete actuator is a stepping motor rotary stepwise under the control of said programmer for incrementally moving said carriage along the shaft.
 6. A drive as set forth in claim 5 wherein said means interconnecting said rollers to said discrete actuator means comprises a crank connected to one of said rollers and chain means interconnected between said crank and the output shaft of said stepping motor whereby upon stepping of the stepping motor said crank is rotated to move said one roller and the others of said rollers via said linkage means from their respective neutral positions to their respective angled positions thereby to effect movement of the driven member along said shaft.
 7. A drive as set forth in claim 6 wherein said chain drive means includes a plurality of sprockets around which a chain is trained with one reach of the chain extending generally parallel to the shaft, said one reach being connected to said crank and supplying a portion of the force applied to said driven member for moving the driven member along said shaft in relatively smooth steps thereby to insure even movement of the driven member.
 8. A drive as set forth in claim 7 wherein a portion of said driven member at least partially surrounds said shaft and carries a plurality of bearing means, one for each roller, each bearing means supporting a respective roller for pivotal movement between its neutral and angled positions.
 9. A drive as set forth in claim 8 wherein said linkage means comprises a rotary member carried by said driven member and at least partially surrounding said shaft, said rotary member being rotary about the axis of said shaft, first spherical bearing means connected to each of said rollers and second spherical bearing means, one for eAch roller carried by said rotary member and interconnected to a respective first spherical bearing means so that upon actuation of said stepping motor said one roller interconnected to said stepping motor effects rotation of the rotary member relative to the driven member via said first and second spherical bearing means connected thereto, the rotary movement of said rotary member effecting pivoting of the others of said rollers via their respective first and second spherical bearing means to assume an angled position corresponding to the angled position of said one roller.
 10. A drive as set forth in claim 9 further comprising means for resiliently biasing said rollers into rolling contact with said shaft.
 11. A drive as set forth in claim 10 wherein said resilient biasing means comprises spring means interposed between at least one of said bearing means and a respective roller for forcing said respective roller into engagement with said shaft and for drawing the others of said rollers into engagement with the shaft so that all of said rollers are driven by the shaft.
 12. A drive as set forth in claim 1 having three of said rollers in rolling contact with said shaft.
 13. Apparatus for moving a workpiece to a work point comprising: positioning means including a carriage for holding the workpiece, said positioning means effecting relative movement of the workpiece held by the carriage with respect to said work point along at least two possible axes of movement for doing work on said workpiece along a predetermined path, one of said axes constituting an X axis and the other of said axes constituting a Y axis; a drive for said carriage including an X axis drive for moving the carriage in increments along said X axis and a Y axis drive for moving the carriage in increments along said Y axis; programmable control means for effecting actuation of said X and Y drives to move the carriage in increments along said X and Y axes in said predetermined path; and each X and Y axis drive comprising a rotary power shaft, means for continuously driving said shaft, a driven member movable along the shaft, means interconnecting said driven member and said carriage, a plurality of rollers carried by the driven member, each roller having its axis of rotation disposed for rolling contact of the roller with said shaft, means mounting each roller on the driven member for pivotal movement about an axis in a plane perpendicular to the axis of rotation of the roller, each roller being pivotally mounted for rotation about its pivotal axis from a neutral position in which its axis of rotation is parallel to the axis of the shaft for rotation of the roller by the shaft without traverse of the driven member and the carriage along the shaft to an angled position in which its axis of rotation is skewed with respect to the axis of the shaft for linear movement of the driven member and the carriage along the shaft, and means operable by said programmer for pivotally moving said rollers about their respective pivotal axes to effect movement of the driven member and the carriage in one direction or the other along said shaft, said means being interconnected with said rollers to cause the rollers to return to their neutral positions in response to movement of the carriage.
 14. Apparatus as set forth in claim 13 wherein said pivotal axis of each roller is offset from its axis of rotation.
 15. Apparatus as set forth in claim 13 wherein the angle of the axis of rotation of said rollers relative to the axis of said shaft when said rollers are in their angled positions constitutes a pitch angle and wherein said means for moving said rollers comprises linkage means interconnecting said rollers for maintaining the rollers at the same pitch angle.
 16. Apparatus as set forth in claim 15 wherein said means for pivotally moving said rollers comprises a descrete actuator and means interconnecting at least one of said rollers to said discrete actuator, the latTer being operable in response to said programmer to effect movement of the rollers from their neutral positions to their angled positions so as to effect movement of the carriage along said shaft and upon movement of the carriage to return said rollers to their neutral positions thereby to halt movement of the carriage along the shaft.
 17. Apparatus as set forth in claim 16 wherein said discrete actuator is a stepping motor rotary stepwise under the control of said programmer for incrementally moving said carriage along the shaft.
 18. Apparatus as set forth in claim 17 wherein said means interconnecting said rollers to said discrete actuator means comprises a crank connected to one of said rollers and chain means interconnected between said crank and the output shaft of said stepping motor whereby upon stepping of the stepping motor said crank is rotated to move said one roller and the others of said rollers via said linkage means from their respective neutral positions to their respective angled positions thereby to effect movement of the carriage along said shaft.
 19. Apparatus as set forth in claim 18 wherein said chain drive means includes a plurality of sprockets around which a chain is trained with one reach of the chain extending generally parallel to the shaft, said one reach being connected to said crank and supplying a portion of the force applied to said driven member for moving the carriage along said shaft in relatively smooth steps thereby to insure even movement of the carriage.
 20. Apparatus as set forth in claim 19 wherein a portion of said driven member at least partially surrounds said shaft and carries a plurality of bearing means, one for each roller, each bearing means supporting a respective roller for pivotal movement between its neutral and angled positions.
 21. Apparatus as set forth in claim 20 wherein said linkage means comprises a rotary member carried by said driven member and at least partially surrounding said shaft, said rotary member being rotary about the axis of said shaft relative to said driven member, first spherical bearing means connected to each of said rollers and second spherical bearings means, one for each roller, carried by said rotary member and interconnected to a respective first spherical bearing means so that upon actuation of said stepping motor said one roller interconnected to said stepping motor effects rotation of the rotary member relative to the driven member via said first and second spherical bearing means connected thereto, the rotary movement of said rotary member effecting pivoting of the others of said rollers via their respective first and second spherical bearing means to assume an angled position corresponding to the angled position of said one roller.
 22. Programmable sewing apparatus comprising a sewing machine, a carriage for holding work to be sewn by the sewing machine, means for driving said carriage so as to effect movement of the work held by the carriage along a predetermined path relative to the sewing machine along at least two possible axes of movement, one of said axes constituting an X axis and the other of said axes constituting a Y axis, and programmable control means for effecting actuation of said drive means to move the carriage in increments along said X and Y axes on said predetermined path, said drive means having an X drive and a Y drive each comprising a rotary power shaft, means for continuously driving said shaft, each roller having its axis of rotation disposed for rolling contact of the roller with said shaft, a driven member movable linearly along said shaft, means interconnecting said driven member to said carriage for movement of the carriage along the shaft, a plurality of rollers movable with the driven member, means mounting each roller on the driven member for pivotal movement about an axis in a plane perpendicular to the axis of rotation of the roller, each roller being pivotally movable about its pivotal axis from a neutral position in which its axis of rotation is parallel to the axis of the shaft for rotation of the roller by the shaft without traverse of the carriage along the shaft to an angled position in which its axis of rotation is skewed with respect to the axis of the shaft for linear movement of the carriage along the shaft and means operable by said programmer for pivotally moving said rollers about their respective pivotal axes to effect movement of the carriage in one direction or the other along the shaft, said means being interconnected with said rollers to cause the rollers to return to their neutral positions in response to movement of the carriage.
 23. Programmable sewing apparatus as set forth in claim 22 wherein said pivotal axis of each roller is offset from its axis of rotation.
 24. Programmable sewing apparatus as set forth in claim 22 wherein the angle of the axis of rotation of said rollers relative to the axis of said shaft when said rollers are in their said angled position constitutes a pitch angle and wherein said means for moving said rollers comprises linkage means interconnecting said rollers for maintaining the rollers at the same pitch angle.
 25. Programmable sewing apparatus as set forth in claim 24 wherein said means for pivotally moving said rollers comprises a descrete actuator and means interconnecting at least one of said rollers to said discrete actuator, the latter being operable in response to said programmer to effect movement of the rollers from their neutral positions to their angled positions so as to effect movement of the driven member and the carriage along said shaft, and upon movement of the carriage to return said rollers to their neutral positions thereto to halt movement of the carriage along the shaft.
 26. Programmable sewing apparatus as set forth in claim 25 wherein said discrete actuator is a stepping motor rotary stepwise under the control of said programmer for incrementally moving said carriage along the shaft.
 27. Programmable sewing apparatus as set forth in claim 26 wherein said means interconnecting said rollers to said discrete actuator means comprises a crank connected to one of said rollers and chain means interconnected between said crank and the output shaft of said stepping motor whereby upon stepping of the stepping motor said crank is rotated to move said one roller and the others of said rollers via said linkage means from their respective neutral positions to their respective angled positions thereby to effect movement of the carriage along said shaft.
 28. Programmable sewing apparatus as set forth in claim 27 wherein said chain drive means includes a plurality of sprockets around which a chain is trained with one reach extending generally parallel to the shaft, said one reach of the chain being connected to said crank and supplying a portion of the force applied to said carriage for moving the carriage along said shaft in relatively smooth steps thereby to insure even movement of the carriage.
 29. Programmable sewing apparatus as set forth in claim 27 wherein a portion of said driven member at least partially surrounds said shaft and carries a plurality of bearing means, one for each roller, each bearing means supporting a respective roller for pivotal movement between its neutral and angled positions.
 30. Programmable sewing apparatus as set forth in claim 29 wherein said linkage means comprises a rotary member carried by said driven member and at least partially surrounding said shaft, said rotary member being rotary about the axis of said shaft relative to said driven member, first spherical bearing means connected to each of said rollers and second spherical bearing means, one for each roller, carried by said rotary member and interconnected to a respective first spherical bearing means so that upon actuation of said stepping motor said one roller interconnected to said stepping motor effects rotation of the rotary member relative to the driven member via said first and second spherical bearing means connected thereto, the rotary movement of said rotary member effecting pivoting of the others of said rollers via their respective first and second spherical bearing means to assume an angled position corresponding to the angled position of said one roller. 